This application relates to a scroll compressor wherein the slider block is configured such that the orbiting scroll will have its wrap flank surface moved out of contact with the wraps of the non-orbiting scroll in the event there is reverse rotation.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a first scroll member has a base and a generally spiral wrap extending from the base. A second scroll member has a base and a generally spiral wrap extending from its base. The two wraps interfit to define compression chambers. A shaft is connected through a slider block to drive the second scroll member to orbit relative to the first scroll member. The drive arrangement for the second scroll member is such that the wraps of the two scroll members are biased into contact with each other such that a seal is provided.
One problem with scroll compressors occurs when the second scroll member is driven in a reverse direction to that which is desirable. Such reverse rotation has some undesirable side effects, and it would be desirable to reduce those side effects.
In a patent application Ser. No. 09/310,545, U.S. Pat. No. 6,179,592, an arrangement is disclosed wherein a slider block pivots relative to an eccentric pin on a drive shaft in the event there is reverse rotation. With such movement the orientation of the second scroll member relative to the first changes, and the wraps are no longer held in contact. In this way, compression chambers are not defined, and the side effects of reverse rotation are reduced.
It is an object of this invention to improve upon the disclosed configurations from the above-referenced application.
In a disclosed embodiment of this invention, a scroll compressor has a slider block with a bore which receives an eccentric pin from a driveshaft. The bore of the slider block is configured such that it has a flat surface which mates with a flat surface on the eccentric pin when the shaft is driven in a forward direction to transmit movement to the slider block and hence the orbiting scroll. In this direction, the orbiting scroll wrap is held in contact with the non-orbiting scroll wrap.
In the event the shaft is driven in an opposed direction, then the slider block moves to a position where a pivot point on the slider block contacts the eccentric pin from the shaft. At that point, the slider block begins to pivot relative to the eccentric pin and the orbiting scroll wrap is moved out of contact with the non-orbiting scroll wrap.
In a preferred embodiment of this invention, the structure of the bore is optimized to have a flat portion for providing a drive surface under forward rotation, and a pair of circular portions on each side of the flat portion. The circular portions are centered on different radii on each side of the pivot pin. The radius on the direction through which the slider block will pivot in the event of reverse rotation is greater than the radius on the opposed side. The greater radius will provide additional space to allow for the pivoting movement. The smaller radius on the opposed side will allow the pivot pin to be relatively thick. If the radii were equal on each side, then the provision of necessary space for pivoting movement would result in the pivot pin being relatively smaller.
In further features of this invention the pivot pin has a unique shape including a ramped surface in a direction opposed to the pivotal movement.
These and other features of the present invention can be best understood from the following specifications and drawings, the following of which is a brief description.